attack. but we all thought there would be a faollow-on attack. all these years later, we are experiencing something. we don't know if this is foreign bred. we do know these two young men have been involved in something truly terrible. the deadly attack on the boston marathon. the attempt, the killing of an m.i.t. patrol officer. others injured along the way. the three who died in boston. the others who remain in hospital. thank you very much. our coverage continues now with alex wit in for tamryn hall. >> everyone is following some new and fast-moving developments in the boston marathon bombings. what we know right now is one suspect is at large. another suspect is dead. there are concerns there may be an accomplice as well. police and law enforcement are searching high and low for those two men. meantime, in watertown,

massachusetts, that's right near boston, a mass impolice and military presence where officials believe the 19-year-old man dzhokhar tsarnaev could be holed up. the crews are planning to wait him out. local police say they could continue through the weekend. nearby in cambridge, that is right near the home of the suspected bombers and their relatives, police plan to perform some sort of controlled explosion. also right now in southern massachusetts, the campus of umass dartmouth is being evacuated. the school has confirmed someone connected to the bombings is enrolled as a student there. we're trying to clear up those details for you. we know this began last night with reports of gunfire on the m.i.t. campus. police say the man shot and killed 26-year-old sean collier, an m.i.t. police officer, who was just sitting in his cruiser. his broad was riddled with several gunshots. the two men car jacked a mercedes suv at gunpoint. police began a chase while those

suspects were throwing explosives from the vehicle. they reportedly told that owner of the car they were indeed the marathon bombers, but then miraculously they released the man unharmed. the pursuit moved to watertown. that is where the two suspects opened fire on police. now, a transit police officer, 33-year-old richard donahue jr., was wounded. gunfight has ensued through this night. authorities shot and killed 26-year-old tamer lap sar nav, dubbed suspect number one. his younger brother fled in the suv, ran over his brother while on that escape, and got away from authorities. that is the man who is dead right now. officers discovered an ied strapped to his chest. during all of this, hundreds of thousands of residents were told, stay in place or get home and stay inside and do so immediately. of course, boston, so many colleges and universities in the

area. all of them, businesses, all mass transit, indeed, have been shut down or closed for business for the day. as said, the two suspected bombers are brothers. they are legal americans. living in the united states for about a decade. they emigrated from the russian republic of chechnya. we have watertown posts covered for you. let's go to the first position. i know you've been on scene for quite some time. it looks like a ghosttown behind you. >> it's completely a ghost town behind me. we've been here for hours upon hours. frankly, i've lost track of time we've been here for so long. it was very early in the morning. we've only seen a handful of residents walking around. it's really remarkable. i know there's a lockdown in this area as there is throughout boston. but the police have no way of enforcing that. so they have no way of saying you have to stay inside. they can just ask people to do it. but people have really heeded that warning. it's really an indication of how

nervous people are about this. also, how much they want to respect what the police out here and the fbi is trying to do. there was a news conference about an hour and a half ago with the governor and boston police. and a few hours. and they said they were going to update us within another hour. we hope that comes again soon. they did say they were able to comb about 50% of this town. they've been knocking on doors for about 13 hours now. they're trying to knock on every single door here in watertown. comb this neighborhood to see if they can find dzhokhar tsarnaev if they possibly can. unfortunately, there's no apprehension as of now. we've seen a little bit of activity in this area over the past few hours. stuff like this, where you're seeing cars speed in, speed out. for the most part, very calm. we saw a few hours ago with kerry sanders being pushed back, if you saw that video, he was pushed back because there was some action going on a few blocks away. since then, it's been pretty quiet. we've seen military helicopters land, take off, circle.

a police helicopter was circling this area for a few hours. that's no longer the case. we're on the main drag of watertown and there's nobody out here. it's a friday afternoon. it's a nice day. it's windy, it's a little overcast, but for the most part it's a pretty warm day here it it's remarkable to see just nobody on the street. it's a really early feeling. it's hard to describe. >> i can about imagine. you've been doing a great job describing it throughout this day for us. i know people didn't even bother coming to work. so many of those businesses are shut down. i know we've had your camera pan over to the side. people are not walking. they are staying inside. trying to find out from authorities when they can go outside safely. >> in fact, boston police have asked everybody in the boston metro area who may have gone to work this morning before realizing the severity of what was going on to please go home. they do not want them to shelter in those offices. there's also been a suspension of amtrak service between boston

and new york. there's a no-fly zone. there aren't very many cars on this street. i mean, this is unprecedented. we've been talking about this all day. to close a major metropolitan city and the surrounding suburbs. to ask everybody to stay inside. to ask businesses to close. to shut down all of the mass transit. that's just a remarkable thing. it's nothing certainly that i've ever experienced. you are used to coming to scenes like this where there is a hostage situation or a barricade or a fire or some sort of major news event. if it's a flooding or hurricane. even in hurricanes, even during sandy, and you know how much damage that caused, there were people out here waving their hands behind cameras. they were talking to reporters. they wanted to get behind the cameras. they wanted to be on tv. they wanted in some way to tease the people who were out on the street. i've never been in a situation where there's nobody out here

trying to find out what's going on. it's amazing. >> it speaks to the gravity of the situation and the fear that residents in the neighborhood are seeing. what's so remarkable is that the older brother, tamerlan tsarnaev, he has been dead since this morning, so all this is the result of one man potentially on the loose. so that one man, dzhokhar tsarnaev, has caused this kind of havoc, if not a lot more strong words. you mentioned kerry sanders. he's elsewhere in watertown. katie was describing you being on the ground. we've seen you in all sorts of positions. just really an exhausting time for you because you're keeping right up with the emotions of the police, that community. it's been like a wild roller coaster there. >> alex, i think i am probably a reflection of what a lot of people in their homes have felt like here, being trapped, waiting for some sort of information and wondering.

glued to their televisions. just trying to find out what is going on. you're in your home. it's dark out. you hear a commotion. you look outside and there you see police officers in s.w.a.t. gear. it's been quite an ordeal for folks here. as you pointed out at times we have found ourselves up close and personal to some very tension moments. i still do not have an explanation. i'm hoping when we do have a news conference, we can get it. we at one point, we went running down with the police officers, jogging right along with them. they took offensive positions with their weapons out on what i glimpsed for a moment appeared to be a body on the street there. on the sidewalk. wearing a turquoise shirt. officers honing in, treating it as if what they had there was

something of a threat. then we were pushed back. i still don't have an answer here in the field. we've yet to get it from the officials. what was that. was it somebody? or was it some thing? they were certainly treating as it if it was somebody and somebody who was a threat to them. when i saw what appears to be a body to me, and i clearly could be wrong, i mean, there's a lot of action going on here, there was no movement. but i'm hoping we'll get an answer to that. a lot of people had raised their hopes, really hung their hopes, that the ordeal was over, that that was the second suspect. meantime, at least in this area, you know, while folks can maybe breathe a little bit of relief because the police were treating this as if that second suspect is not here, some disappointment. people because would like to know the second suspect is either in custody or otherwise. and they don't have to worry. they don't have to think that there's going to be somebody

roaming here that could be a threat. >> right, they sure want to get some relief. all right, kerry sanders, thank you so much. elsewhere in watertown, let's go to nbc investigative correspondent michael issakof. in your experience doing investigative reporting, would it at all be likely that the man that kerry saw could be, indeed, the second bombing suspect, and that the word would not be put out? or would you think they'd get out word immediately had he been apprehended and/or killed? >> well, look, i don't think they're going to put the word out till they can account for him. either take him into custody or tell us he's died in this holdout. he is a threat to public safety. and i think they're taking this extremely cautiously. and they're being extremely

reticent about divulging any public details since this morning when we first heard the rather chilling account of what took place last night. i've been waiting here. right behind me is the staging area where a small army congregated early this morning. we had convoys of military humvees, bus loads of police and state police, motorcycles. we had blackhawk helicopters buzzing around. we thought for a while that we were going to see an armed confrontation, if not an assault, by authorities. but that doesn't seem to have taken place here. they're all sort of assembling here, waiting as it were. i think they're waiting to see what happened at the location kerry was describing. but beyond that, alex, there is still the problem, and i think this is the biggest one, of that

ied that was found in charlestown, in boston, earlier today, raising the concerns, are there others out there? were the streets of boston booby trapped in some way with ieds left by these guys? until they can completely answer that question, it's going to make it very difficult for them to tell the public they can return to the streets. even if they get this guy. even if they get dzhokhar -- >> tsarnaev. >> car natsarnaev, so i think w tell them this could go on for a while. >> is there any known association to the best of your investigative reporting with watertown or is that merely a place where an suv stopped in an

attemptive getaway? >> well, they lived in cambridge not that far from here. remember, this begins with the robbery and shooting last night of the -- the shooting of the m.i.t. police officer. there's was a police chase here. we don't precisely know how it is they decided to come here. when we talk about associations, i just want to bring up another point. i just find so intriguing. when police commissioner davis briefed us early this morning and talked about dzhokhar, he said, you know, we consider him to be a terrorist, but what kind of terrorist. that was the question we've had since the beginning. was it domestic, was it international, what was the motivation? was it because of the

anniversary of oklahoma city and waco. or did it have radical islamic jihadi ties? i think the clues are increasingly pointing to the radical islamic jihadi connection. in particular, i want to point out one interesting thing, which we've just come across. we've gotten those travel records, which show that tamerlan, the older one, had left the united states last year for six months, flew to russia, and came back in july of 2012. and then it's just a month later, in august of 2012, just after his return from russia, that he -- there is this youtube account created in his name in which we repeatedly see these radical islamic postings. including the black banners of

karzan, a prophesy evoked by osama bin laden and extreme al qaeda terrorists. and put that together with one other clue. what the uncle said today, which was very interesting. at one point, he said, somebody radicalized them. so for years, now, we've been hearing the warnings of counterterrorism experts about individuals who may go abroad in the united states, come from -- leave the united states, go abroad and become radicalized. and this may be the example that proves their warnings more than any other. it certainly had the biggest impact of any other terrorist case. of any terrorist case we've seen in recent years. >> your insights are very much appreciated. we're going to pick up on them. i'm joined by retired special a.t.f. agent.

as well as cliff van zandt. with a welcome to you both. let's pick up on this radicalized notion. we have a description, a very heartfelt description, where one almost feels sad and sympathetic to the unk cle of these two brothers from maryland and he said, you know, i abhor what they've done, he wants no association with them whatsoever. interestingly, the sister of the suspects, who was spoken to from west new york, and she described them as being very smart young men. is this a perfect combination for radicalization? because she had not seen her brothers or spoken to them for some time. a matter of years. the uncle who lives here in the states as well, in maryland. so seemingly, you know, a close relative had not spoken to them since they were young boys. what does that tell you about their makeup? >> well what really counts is the influence of the older, now

diseased, brother. realize, he was not only the older brother, he was the more physical. and he kind of took on the father role too. he was the one who said he didn't understand americans, he didn't get along with people. he was the one who took the trip. so he was the one i think that could have been radicalized in his travels, in his disaffection, and i think he could have scooped up his younger brother who who have had little to do, and, again, i'm not giving this guy any reason to do anything, but he could have followed his older brother's example and come along with him. in a relationship like this, and jim can talk about the d.c. sniper, but you usually have an older or dominant individual and a younger one who's a follower. that could very well be the case with these two brothers also. >> clint, they're more likely to be able to i guess the person who's trying to do the influence can do so if they're in more of a vacuum. not being reached out to by

other family members. they were living in a very isolated manner on their own. >> what bothers me is they come to this country as refugees. they claim that status. and then turn and ause that against us. it's always that the very best nature, the very best that's in us, in the united states, is turned around and used, weapon, against us, by those who would do us harm. >> it's interesting, you talk about that. the family was granted legal permanent residence march of 2007, became naturalized citi n citizens on the anniversary of 9/11 just last year. there certainly seems to be irony in that. with regard to the potential bombs, explosive devices that are planted around boston, is that probably top concern for your former agency the atf right

now? >> i think it is collectively for fbi, boston police, you know, collectively water enforcement is really concerned about that. to build on what clint said, i think he's right. i think this brother was dominant. we talked about that yesterday. but think about -- i want to lead back to them. >> sure. >> this guy goes out of the country for six months. the process of rad dalization for suicide that al qaeda use and all of us in law enforcement, you know, paid attention to and studied, especially us bomb agents, we were very in tune with this stuff because we know it's going to be out there. and it takes time. it's not a brainwashing thing. it's sort of a self-transformation. where you're encouraged. and helped along. where you come to believe that you want this.

and, you know, it does come from people who have been moved out of their home country sometimes. i mean, even muhammad atta was leaving in germany, he went to the hindu kush and was radicalized. this slow incullcation into al qaeda's main pillar, which is the seminal difference. and clint brought up the relationship and that's why he brought it up of muhammad and malvo. to take it to this extreme, this svengali over the younger one. but the difference between those two and these two is the suicide ideal. and that is a huge difference. because when they can incullcate that into someone, like they probably did know dzhokhar, he is then the radical, radical

guy. i think it's interesting that the brother, who has so much influence, can do it to this younger 19-year-old. that would be a harder task because he would be doing it just with himself and maybe the internet. but there could have been some phone calls back and forth, interness connections as well that will turn up in the intelligence. it's a big -- it's big news today in law enforcement that -- the suicide bombers are here. and i also think that the pressure cooker, to get back, alex, to your great question here, are they around boston, is it the main thing. yes, but i think these guys were going to do more bombs. i don't think the marathon was the only two bombs. i don't think they made that pressure cooker -- they had these other improvised grenades. they were going to do another attack. so keep that in mind. >> i want to let all of you know we're taking a live look right now. that is cambridge. i believe it's been cordoned off a couple of blocks from the

home, the apartment, where these two brothers lived together presumably with their mother. we don't know a lot about where their mouther is. we know the father lives in russia. he was spoken to earlier today by media and call the eboys angels, one of them in particular, said he was studying to be a doctor, in his second year of medical school. we have information the older disead deceased brother was attending a community college, studying engineering. regards to the atf's role right now, once you get past looking for these bombs, you look at these six months from january to july of last year that tamerlan spent overseas. does this time frame make sense to you? would it take perhaps nine months on the heels of returning

to the united states to be able to pull off something like this? do you see the actions of these guys beginning with the bombing of the boston marathon on monday? is this the work of nine months of planning? >> well, there's a long period of incolcation of the suicide ideal. it takes time. the way al qaeda used to do it, the person would have to actually pledge to bin laden. they guarantee their life in service to allah, they say. of course it has nothing to do with islam, it's an al qaeda terrorist group. but they use religious, they distort it, and they make their killers. if he goes there for six months, he's probably communicating back with his handlers, and there's still a period of interaction,

that ice probably making the bombs -- >> we should let people know we're seeing military assault vehicles and they seem to be well armed. they're driving in the area of cambridge where we believe there will be some sort of a controlled explosion because a device they found. i believe it was described as a pressure cooker type of device. which was used certainly in at least one of the boston marathon bombings. that first explosion they believe was a pressure cooker device. my apologies for interrupting. >> they're going to disrupt that device, they're going to use the bomb technicians from fbi or the massachusetts state police, they're going to disrupt it. atf has bomb technicians there as well. they've been i'm sure brainstorming it all morning. what they'll do is set a disrupter on it or somehow try to countercharge it. it may go high order. i think we can guarantee here is

we know these guys make a lot of bombs and their bombs have been effective. it pretty well could go high order. we all know the fragmentation that's invofrled in one of these pressure cooker bombs. they'll get way back. they'll do their shots. >> whether or not we're able to see that from a live camera perspective is potentially unlikely given the kind of carnage that can result from that. i'll ask you both to stand by. i want to bring in nbc's erica hill who is in watertown. what are you seeing? >> good afternoon. on the street just behind us, there were a number of humvees. i got here about 20 or 30 minutes ago. erb awaiting that controlled explosion. we've seen a number of vehicles come in. i saw a s.w.a.t. vehicle from cape cod come in. two canine cars came in. also a police car from dennis,

mass, also on the cape. you're seeing all hands on deck. what we know at this hour is that as we've been telling you they are going neighborhood to neighborhood, street to street. they're telling us they've cleared about 60% to 70% of what they want to but they are still on it. i flew in from new york city from jfk. as we were waiting for the flight, i can tell you, no one was talking. all eyes were on the tv. when we landed in boston, also very quiet. i went to school here in boston. the streets as we made it from logan to watertown, eerily quiet and empty. no one out. everybody heeding that call to please shelter in place. that affects just under 1 million people at this point. some of the things we're watching. officials have a lot on their plate at this point. probably the next thing we will

hear is the controlled detonation we've been hearing about. >> you make an be observation at people in the airport. at times like this, 9/11 does not seem that long ago. this is the first time we've had anything of this magnitude since 9/11 in the united states. because you have essentially now one man potentially having wreaked this much havoc on potentially the eastern seaboard. we've got boston locked down. trains being searched. stopping amtrak travel up the eastern corridor there till they figure it's safe to go ahead. put this in perspective. you've got all these people in watertown. it's a small pocket of the greater boston area. and look at the drama. that is emmating from that area. >> it's true. one of the things that's remarkable is how everyone has heeded that order from officials to please just shelter in place.

just stay where you are and stay safe. again, they're telling you not to open the door to anyone unless they have properly identified themselves as a law enforcement officer. on the upside, we can say that everybody is really abiding by that order and doing their best to help law enforcement officials. as you say, it is very different. it makes 9/11 feel not that far away. another thing to keep in mind, they're not just watching us at the airport. we all have updates on our phones. we have wifi in the air. i only had about 20 minutes of wifi but as i'm in the air, i'm checking updates, and i heard a man next to me say, so what's the latest, have they caught this guy? so this is clearly at the top of everyone's mind. community of about 30,000 people. a few people making their way out. all in all, not very many. >> do you get a sense of fear,

erica, from people you've talked to? we all become somewhat anesthetized by false alarms. do you get a sense this is different though? >> this seemed to change things. there was initial shock and of course fear and confusion over what happened earlier in the week. as things go along, there are different developments. like so many people, you go to bed last night seeing one thing and when you wake up this morning, it's completely different. especially when you talk to people of a movie you would see. where they would make developments in the plot line and you say, that could never really happen, but it is actually happening today. hundreds of thousands of people are living through it right now in this neighborhood. >> all right. nbc's erica hill there in watertown. for those of you just joining us, it is nearly 2:30 here on the east coast. 11:30 a.m. out west. we're following the rapidly changing and developing events

in watertown, massachusetts. where there's a manhunt right now for 19-year-old dzhokhar tsarnaev. his older brother, 26-year-old tamerlan tsarnaev, has been dead for 13 hours now after a shootout with police. this all went down in the suburbs there of boston. virtually the entire city of boston has been on lockdown. certainly on high alert. the town of watertown we can tell you is on lockdown. somewhere in that neighborhood we believe there is an explosive device that has been found and that will be set off in some sort of controlled way to try to prevent any further harm. again, these two men i've been speaking of are the two primary suspects in the boston marathon bombings on monday. i'm joined now by jonathan deans

who has been getting the background of these gentlemen. one of whom left the united states for six months. evidence that he was getting radicalized overseas? do we know where he went? >> we know he flew to moscow. we know he has relatives in russia. the question is, what did he do over that six month period. that's what federal investigators are trying to track down. to find out was he radicalized. did he have any handlers he met with while overseas? again, this investigation is just getting started. you look at the freshness of this investigation. you look at their travel documents. it wasn't till this monning they were put on terror watch list. so it shows how rapidly law enforcement is moving, trying to

catch up and stop these guys, to prevent them from -- now the one survivor, to stop him from striking again, after that horrible attack during the marathon. you'll look at that video. as pete and i have -- it's been described to us, the white hatted suspect walking through the crowd to get into the front row. calmly doing it. sets down the backpack. watches the other explosion go off. he just sort of meanders away waiting. and then seconds later the second bomb went off killing and injuring so many. >> we keep talking about tamerlan tsarnaev, the 26-year-old older brother, who's now deceased. was there any evidence the one still on the run, 19-year-old dzhokhar, do we believe he was purely influenced by his older brother? unclear about the influence. once he came to the united

states and was given citizenship on 9/11/2012, that he had -- the travel records show he had not left the united states since he arrived here as a child. at least not through a passport. >> yeah, was there any connection with m.i.t. because we know in the early hours before the car jacking of that black suv mercedes, they went to the m.i.t. campus where they just shot and killed -- was it random or not -- that police officer, the campus police officer? >> the best explainer we have is maybe they panicked. they thought maybe this police officer recognized them based on the bulletins. and they took actions into their own hands. maybe they were just preparing for war and battle and they were ready to start it. unclear. that part of the investigation continues. what will be interesting to note

is where were these bombs built. they had to assemble them somewhere. because it's not very safe to -- >> they're volatile. >> they can be. these types of devises i'm told in a backpack as long as you're not jo jostling them too much can go a bit of a difference. so they can find out if he has any accomplices. in the meantime, they're going over all those cell phone calls to see what connections they might have. and that's the concern, who else might be out there. >> they want to find out what else might be out there in terms of planning to disrupt communities. thank you for that. as we give you guys looking again at cambridge, massachusetts, live pictures, as

you see heavily armed patrol officers there moving in some fashion toward something. i'm joined by greg pugh, a watertown resident, witness to the events last night. i'm sure it's been a long night and day. tell me about your experience last night in watertown. >> last night, i got home and all of a sudden, ten minutes after i got home, i heard 50 to 100 rounds just go off with their big bangs. obviously, the bombs had blew up. >> coming home, this was about maybe 10:30 -- >> i got home around 12. >> okay -- >> probably 15, 20 minutes after that, everything started going. and then i ended up -- i thought -- i thought it was just one guy so i ended up walking down the street towards laural street and spruce street and all of a sudden 20 cops came, s.w.a.t. and everything, like,

get back to your house, go inside. i ran all the way back home and all of a sudden more gunshots started going off again. >> how long did it take you to high tail it home? >> i went straight home. >> could you see things from your window? >> i couldn't hear everything but from my window i just saw it going up and down the street. they actually pulled a car over and pulled people out of the car and just threw them to the ground. i don't know if that was security reasons or not. >> who's they pulled people out of the cart? >> the police officers. >> so they pulled people out of a car in order to keep them safe? >> no, no, yeah, they probably -- because the car was driving into the -- where everything was happening. so obviously, the police officers were doing that to protect themselves. >> when you were hearing the noises, you heard explosions, did you also hear exchange of

gunfire? >> yes, i did. >> what was that like? were you aware? >> at first it was like three, four shots at a time. at one point, it sounded like it was an automatic weapon just went off. >> we've spoke with people here on mp snbc earlier in the day who have been up all night much like yourself, and they had a bullet enter their apartment. it went through a window and they found a bullet on the ground of their apartment. anything like that with you? or did your place remain unscathed? >> nothing like that around here. >> okay. greg pugh, thank you very much for phoning in. we appreciate your insights. let's go back to clint van zandt. nbc's crime analyst. and former fbi profiler. as you start putting things together -- i think we may have lost clint -- clint, are you hearing me? >> yes, i am.

>> as we put together all of these pieces, i know it is impossible for you to know exactly the direction in which it is going, but your sense of who these guys were, these brothers, one of which is dead, and the capacity for what they've not only done but could do, can they pull this off alone? because there's talk of accomplices. there's talk of looking to see if they may have had some sort of assistance. can they do this kind of carnage, just two men? >> well, the answer i think alex is yes. two men can build these devices. reaplize it was in 2011 that a former u.s. soldier built two exact similar devices based upon the plans he found on an al qaeda website. he built two bombs and he was going to use them against u.s. soldiers at ft. hood. the authorities stopped him

before he did it. he was one man working under the inspiration he got from the magazine, buying all the parts locally. so one men, two men, could do this. but in this particular case, it looks like the information is suggesting there's external radicalization. whether there was any further guidance, funds or anything else is yet to be determined. >> do you have a television in front of you, and if so, can you see the live picture? i believe this is cambridge. >> yeah. >> that looks like it's a car under which -- it's under this blue tarp. we also saw a tow truck pulling away from the center with a car on top of it. but can you pick up anything from that? does this look like something that might be just ahead of a controlled explosion?

maybe if we release the banner for a second. >> it's more than likely they're trying to preserve it for evidence. otherwise, they'd have a tow truck, hook it. when you put a tarp over it, you want to take it into a garage and be able to examine is forensically and not lose any evidence. that somehow perhaps related to this case and the authorities may believe there's some type of forerensive evidence they can glean from that car. >> we're seeing two blue tarpaulin covered entities there, presumably cars. one was the top of the screen. this one, is it possible we're looking at two different types of explosives? >> realize, earlier today, we heard there were two cars of interest to law enforcement, that they were looking in two specific vehicles with their guns at the ready, examining it. so these two vehicles may be the same two we heard about earlier

today. law enforcement had a specific interest and made a connection between the two bombers. >> this is more evidence they're trying to pull as opposed to potentially a controlled explosion, right? >> if it's a controlled explosion, they'd bring in half a dozen tow trucks and pull everything. they wouldn't worry about preserving evidence. >> this area is cambridge, massachusetts. it is confirmed. it is right outside the apartment building where these two suspects were known to have lived. so this clearly has something to do, very directly connected to these two suspects. the one that's on the run, 19-year-old dzhokhar tsarnaev, the fact we have not seen him for a period of many hours now, does that mean that he is in this watertown area where they've cordoned off the area,

they're going house to house, apartment to apartment? or does that mean he's gotten out of town and gotten away? >> the more houses they go to and don't find him, obviously law enforcement is getting a little more, you know, concerned that he got out of the area. we know that his brother had multiple, multiple gunshot wounds, as well as evidence that an explosion has gone off. we heard the younger brother drove over the top of his older brother when he made a getaway. if he and his brother engaged law enforcement in that firefight, it stands to reason the fugitive we're looking for now may have been hit a few times. so i think law enforcement also has to consider if they were able to establish he had any blood inside that vehicle, he

could have, you know, fled on foot and he could be sitting, already bled out from his wounds. so that's another consideration they have to have. >> i was wondering how with the brother's body having been riddled with so many gunshot wounds, how the younger brother escaped unarmed but you're right, he may be injured. we go back to watertown. we're looking at nbc's katie ter who has an update for us. >> we weren't sure what they were being used for. we just got an update from jim mick la chef ski. he said they're just for transportation only. you're seeing national guard troops in the area. apparently, they're mostly being used for traffic control and other logistical things. they're not actually going in and helping out with the search.

the protective forces that we're seeing, the heavily armed guys in the combat fatigues are federal, state and local officers. they're the ones we believe are going door to door. we had a news conference, an update by the governor. they said they were 60% to 70% done combing this entire town. they've been knocking on doors now for, gosh, well over a dozen hours. they've been out here since very early this morning. this place is in a complete frozen zone. it's like a ghost town out here. we expect an update at any point. they said it could be an hour, it could be a little longer. if they had 60% back then, maybe they're getting a little bit higher. we have seen them come a little bit in this area and have seen them knocking door to door. it's so eerie being out here and not seeing anybody but media. there's no residents out here. there's no children. there's nobody but the news

media here. it's just something you don't expect to see if the country when there's a big event going on. i think it speaks to how, you know, i heard someone speaking about this a little earlier. i think willie geist said. this is the very definition of terrorism. you have an entire metro area on lockdown. because of one guy. one guy having more than 1 million people staying inside their homes. one guy with thousands upon thousands of federal, local and state officials and authorities searching for him. this is all for one person. we're not even sure there's another accomplice out there. if this was the goal, it was to insight terror, this was certainly a very successful example of that. safety is the biggest priority here. it's very jarring.

it's very awe inspiring to see. not in a good way of course just how much panic and how many terror one person can cause. >> you have absolutely hit the nail on the head there because we've been talking about that all day. clint van zandt, as you're still with me here, you and i have talked countless times on the air about terrorism activities and criminals and we always hate talking about it because you think that copycats can ensue as a result of that. but in this case, this must be covered wall to wall like this, because of the type of activity that these two men presented, as they were being capable of doing. they've literally wreaked havoc on the city of boston and neighboring communities, on transportation facilities. but it is -- it's tough, because you wonder if there will be those who look at this and say, i want to do the same thing. >> i think it shows just how

vulnerable we are, alex. we go back to the d.c. sniper, where two men, beat-up chevrolet, and rifle and $50 box of bullets paralyzed the east coast. now we're going through that drill one more time. where a 19-year-old has got 20,000 armed people looking for him and he has paralyzed an entire community by his actions. we have to do it. we have to get this guy in custody. the threat is the explosions. the explosive ordnance that he has. he has ability to further mayhem. just like you're saying, i mean, this is an absolute playbook for someone else who wants a terrible 15 minutes or in this case five days of fame. >> we're looking at these door to door searches being conducted. you've heard it said some 70% of

approximately watertown or at least that area in watertown in which they were concerned the suspect may have fled has been put into the all clear. but they have to continue till they're at 100%, but clint, this -- >> and then what? what if the next 30% -- >> you've got police officers and s.w.a.t. agents, they're going to literally hundreds of homes and apartments. so alex and clint van zandt, we're two fbi agents, we go knock on the door, nobody answers, what do we do, do we go away knowing the shooter could be inside by himself? he could be inside with hostages. do we kick in the door of every house and apartment in the community where nobody answers? this is fraught with not only danger but with liability. now, that's the last thing the authorities have to care about is whether we're going to get sued for kicking in somebody's door. but, again, these are so many

intricate challenges that come with a case like this that most people don't even think about, that law enforcement has to live with. >> absolutely. clint, we'll ask you to continue standing by for us as joining me on the phone is "time" magazine's bobby goshe. talk about chechnya, the community there, that country which has been so marred with ret revolution, violence, it's been a hotbed for islamic terrorism. the fact that these young men were from that area initially, what does that tell you in terms of inspiration for the activities we're suffering through here in massachusetts? >> just as you point out, has been a hotbed for violence for a very long time since the 1990s. but what happened here with these two guys have unusual.

chechen fighters have ended up in places like iraq and syria it's tooing alongside rebels there. but the idea of attacking foreigners, attacking americans, for a chechen cause, if that is indeed what these men were trying to do, is very unusual. that's never happened before. they have confined most of their terror attacks to russia. their animus is against russians. they don't have any particular animus against -- the chechens don't have a particular animus against the united states. so these guys are definitely outliers even for chechnya. >> take a listen to the uncle of the tsarnaev brothers, this is ruslan sarni, from maryland, tracked down by the media, and here's what he said about the events of this awful day. >> he put a shame on our family,

tsarnaev family. he put a shame on the entire chechen ethnicity. because everyone now names the play with word chechen. so they put that shame on the entire ethnicity. i say, dzhokhar, if you're alive, turn yourself in and ask for forgiveness from the victims, from the injured and from those who left, ask forgive misfrom these people. >> the uncle there brings up a point, particularly in the first half of his answer there. you know, it is something everyone will now say, oh, these were chechen immigrants here. does this with a broad swath put a negative connotation on that? >> well, it certainly does. the risk is the chechen americans and chechens living lawfully in this country will

receive some amount of hostility and suspicion. in chechnya, i'm sure there will be horror and anger. even those who support the cause of chechen independence will be very upset about this. because they view their fight against russia as an honorable struggle and what happened in boston is as far as you can possibly get from honor, so i think even in chechnya, even those fighting the russians, there will be anger and loathing for these young men. >> many thanks for your insights. joined now by ron allen who is in cambridge where we have been seeing that activity. also clint van zandt remains with us. tell me what you're seeing. what specifically is going on? >> the police have converged on the house where the two brothers lived we believe with their

mother and perhaps with two sisters. they've been out here all day. probably half the night as well. trying to learn what they can about these two individuals. we've seen cars searched in front of the house. we were told a couple hours ago there was going to be a controlled detonation of a device near the house. we've been told earlier that the house seemed to be rigged with bombs and explosives. they've not yet been able to search it completely. obviously, what they can get inside, they hope to learn a lot more about these two individuals and what they were up to, what they were thinking and everything possible about their lives. at this moment, the situation is relatively calm. they're going through this meticulously. the pace of the operation seemed to have slowed down in the last hour or so. which suggests they're going to be out here for a while. they recently opened up this main drag, cambridge street, which runs right through the

city of cambridge, an indication they'll go through this process as carefully as possible. earlier, from a rooftop vantage point, we saw s.w.a.t. officers with automatic rifles trained at the ready. at this point, we're watching and waiting to see what the next step is. here, there are a lot of people on the streets of this community. some people are getting cabin fever because they've been heeding that warning to stay inside. there are a few people out and about. the area right near the house in question was evacuated. right now, people are watching and waiting to see if the police investigators go through the careful process of trying to dissect what's in the home. >> may i ask you about the universities right there, word is they are completely shut down out of an abundance of caution

or safety. a lot of these schools, they are approaching the end of the school year and exams. but has there been any sort of threat or anything that would give cause for parents of these students to worry? >> the entire metro area of boston is locked down. that's about 1 million people or more including those schools, yes. harvard, m.i.t., are very close by. m.i.t. was the scene of that awful incident involving the police officer who was shot in the head last night while he was sitting in his car, apparently ambushed by the suspects, so there is mourning and grief there. across the river in boston university, so many other great schools are also shut down. mbta, the transit system, is closed. it's all on lockdown. there's a boston/red sox game

planned for this evening. that's unlikely to happen given the fact there was some kind of device found -- >> charlestown area. >> -- earlier this morning, so, again, the whole place is on lockdown. >> the boston red sox said they'll wait to see what authorities tell them, whether or not they can play their game tonight. we did see a picture of a cambridge street on which there was one of those mbta buses. it is not being used for public transportation. that is boston police who are boarding and getting off that bus. taken from one place to the next in this very concentrated area. i know you're still with us. i wanted to get back to something bobby goshe had said in regard to chechnya and the fact that chechen rebels have much more of an internal within the area of the breakaway

republics of the ussr or with, now, the mother country, russia. it's so unusual they would use their unhappiness with the plight there and turn it on the west, specifically the united states. does it tell you that these brothers, at least the older brother, must have been radicalized to turn his anger towards the west, towards the united states? >> well, we have to really try to get into the minds of these two guys. but what we have to consider is in their minds this may not have even, in their minds, they may not have seen this as an attack against us but a way to get attention for their cause. a way to get international attention. there were runners from 95 different countries who ran in the marathon. so this may well turn out, if there is this international aspect to it, that these two individuals were simply so dedicated to their own cause

that this was a means to get attention and all of the damage will be, as timothy mcveigh said, collateral damage. >> do you classify these guys as domestic terrorists or because of their international association as well, are they foreign terrorists? technically, they're legally u.s. citizens now, naturalized citizens. >> sure, yeah. i think we have a hybrid. i think we have something like major nadal hassan who did that terrible shooting at ft. hood. he was radicalized by politics, by his internet teachings and learnings. so i think we see that interesting hybrid and i think we may find out with these two also. >> all right, clint van zandt. i'm alex wit.

please do join us tomorrow. we'll have extended coverage for you and bring you the latest developments. in the meantime, i turn it over to my colleagues. >> we've got late-breaking developments. exactly four days to the hour since news of the boston marathon bombings broke. that has gripped the nation and the world. as we come on the air in the 3:00 eastern hour, local, state and form authorities are now in hour 17 of their search for 19-year-old dzhokhar tsarnaev. he took off to the northern suburb of watertown in a car jacked vehicle which he was in with his older brother. that man, tamerlan tsarnaev, was killed. after which